there is no reason that bubba cant fly at that age. But can you handle bubba on your lap for 24 hours?
It is actually easier at that age rather than when they are Charlottes age - so hard to fly with her now as all she wants to do is run around! lol
Just make sure she has something to suck on for take off and landing so her ears dont hurt and she'll be fine

I hope though you dont have to and DF makes it back in time to see your little girl come into the world - good luck!